September 15 is an important tax deadline for many self-employed individuals, independent contractors, investors, retirees, and small business owners. It is the due date for the third installment of 2026 individual estimated tax payments.

But simply making the same payment you made earlier in the year may not be the best approach.

By August, you have seven months of actual income and expenses available to evaluate. If your income, business profitability, investments, or financial circumstances have changed, this is an excellent time to determine whether your 2026 estimated tax payments are still appropriate.

More importantly, an August tax review can identify planning opportunities while there is still time to act before December 31.

1. Has Your Income Changed During 2026?

Estimated tax calculations made early in the year are based on assumptions about what will happen during the remainder of the year.

Real life rarely follows those assumptions perfectly.

Perhaps your business is more profitable than expected. You may have received a raise or bonus, started consulting or freelance work, sold investments, received additional retirement distributions, or experienced another significant change in income.

The opposite can also happen. Business revenue may have declined, an expected bonus may not materialize, or deductible expenses may be higher than anticipated.

These changes can affect the amount of tax you ultimately owe.

Rather than automatically making the same September payment, consider updating your 2026 income projection and determining whether your estimated payments still reflect your expected tax liability.

2. Small Business Owners: Review Your Year-to-Date Profitability

August is particularly useful for small business tax planning because most business owners now have enough year-to-date information to develop a reasonable estimate of full-year profitability.

Review your income and expenses through July and compare the results with both the prior year and your expectations for 2026.

Important questions include:

• Is revenue increasing or decreasing?
• Have operating expenses changed significantly?
• Are you taking all legitimate business deductions?
• Are your estimated tax payments keeping pace with profits?
• Are major equipment or technology purchases planned?
• Have you maintained adequate records for business mileage and other expenses?
• Does your current business entity structure still make sense?

For S Corporation and Partnership owners, this can also be a good time to review anticipated K-1 income rather than waiting until the following filing season to discover that taxable income was substantially different from expectations.

3. Don’t Forget About Withholding

Estimated payments aren’t the only way to address a potential tax shortfall.

Employees and retirees who have federal income tax withheld from wages, pensions, or other payments should review their withholding periodically—particularly after a significant change in income or deductions.

This is especially relevant in 2026 because tax law changes may affect deductions and credits available to some taxpayers.

If withholding appears insufficient, increasing the amount withheld for the remainder of the year may be an alternative to—or work in combination with—additional estimated tax payments.

The goal is not necessarily to receive a large refund next spring. Good tax planning attempts to bring payments reasonably close to the expected tax obligation while maintaining adequate cash flow throughout the year.

4. Review Retirement Planning Before Year-End

Tax planning shouldn’t stop with estimated payments.

August still provides several months to evaluate retirement savings and determine whether adjustments may make sense.

For 2026, the employee contribution limit for most 401(k), 403(b), and governmental 457 plans is $24,500. The IRA contribution limit is $7,500, with additional catch-up contributions available for eligible taxpayers age 50 and older.

Self-employed individuals and business owners may have additional options, including SEP, SIMPLE, Solo 401(k), and other retirement arrangements.

Retirement planning should consider more than simply obtaining a current-year deduction. Your age, income, tax bracket, business profitability, future retirement needs, and the differences between traditional and Roth contributions can all affect the appropriate strategy.

5. Start Year-End Tax Planning Now

One of the biggest misconceptions about tax planning is that it should happen in December.

December may be too late for some strategies—or may force decisions to be made quickly.

August provides time to evaluate issues such as:

• Estimated tax payments
• Business profitability
• Retirement contributions
• Business equipment purchases
• Capital gains and losses
• Charitable giving
• Business entity structure
• Qualified Business Income deduction planning
• Partnership and S Corporation K-1 income
• Withholding adjustments
• Potential year-end income and deductions

The objective is to identify issues now and develop a strategy for the remaining months of the year.

Tax Preparation Looks Back. Tax Planning Looks Forward.

Tax preparation primarily reports financial transactions that have already occurred.

Tax planning asks a different question:

What can we still do before the year ends?

That’s why the September 15 estimated tax deadline can be more than simply another payment date. It can serve as a useful checkpoint for evaluating your overall 2026 tax situation.

If your income or business profitability has changed significantly—or if you’re simply unsure whether your estimated payments are still appropriate—August is an excellent time for a tax planning review.

Need Help Reviewing Your 2026 Tax Situation?

CPA Mobile Tax Services provides year-round tax planning for individuals, self-employed professionals, and small business owners.

Services may include estimated tax projections, business profitability reviews, entity structure reviews, Qualified Business Income deduction planning, Partnership and S Corporation K-1 interim reviews, IRS transcript reviews, retirement planning, and year-end tax strategies.

Mobile, at-your-home CPA services are available in the Loganville, Georgia area and surrounding communities, with secure virtual tax planning services available for clients throughout Georgia and Utah.

Don’t wait until tax season to discover what you could have done before December 31. Schedule a 2026 tax planning consultation today.  

This article provides general tax information and is not intended as tax, legal, investment, or financial advice for any particular taxpayer. Tax planning recommendations depend on individual circumstances.